Shipping container



June 7, 1966 D. GUTTERIDGE ETAL SHIPPING CONTAINER Filed Feb. 26, 1964-lation to the peripheral edge of the end member. pasion, the containerend member has comprised a lamilvof the body ribs.

The present invention relates to containers and, more particularly, tothe formation and construction of an improved container of the typehaving an end member formed of a plurality of laminations of fibrousmaterial. In its principal aspects, the invention is concerned with animproved end connection between the body and end `walls of a fibrousshipping container, and to methods of manufacture thereof.

During recent ye-ars there has been a persistent and ever increasingdemand for practical and reliable shipping containers which are made offiber, paperboard, or other suitable natural or synthetic non-metallicfibrous materials, yet which Iare capable of withstanding deformationforces during periods of storage, transportation, and use.

As a consequence, it has been a common practice in the containerindustry to manufacture non-metallic shipping containers having anendmemberor closure comprising a disc formed of fiber, plywood, orsimilar material, with the disc being attached to the containerbody wallby means of a pair of axially spaced, inwardly extending,circumferential ribs formed in the body wall in confining re- On cnatedfibrous disc in Which the different 'laminations have identicaldiameters substantially equ-al to the internal `diameter of the bodywall, thus permitting the end member to lseat on one of the ribs orshelves formed in the body wall and to be held in place thereon by theother Of course, in these types of container constructions, the endmember does not contribute in any iway to the strength of the connectionbetween the end member and the body wall. Indeed, such containers arecharacterized byY their inherent weakness at the junction of the end andbody walls and the consequent tendency of the end wall to pull or snapout of the confining ribs when the container is heavily loaded or whenthe container is dropped or otherwise subjected to deformation forcesduring transportation, storage and handling. When 4this occurs, oftenall or a substantial portion of the container contents are either lostor contaminated. Moreover, even in the undamaged state, the connectionoften does not meet the requisite conditions of tightness demanded bythe users of such containers so as to insure that the latter aresubstantially substance-tight.

Yet another approach to the problem that has heretofore been taken bythe manufacturers of fibrous shipping containers have involved the useof an end member or closure formed of 4a plurality of discs havingunequal diameters. In this type of construction, the main disc, that is,the disc which contributes most to the thickness of the end member, isnormally the disc having the smallest diameter with the particulardiameter selected being equal to or slightly less than the internaldiameter of the body iwall. The remaining disc or discs have a greaterdiam- United States Patent ice veter than either the main disc or thebody wall, and the vit is held in place by only the relatively weakperipheral edges of the layers having the larger diameters.

Yet another disadvantage of this latter type of conventional containerconstruction resides in the fact that the container end member must befabricated from preblanked discs having unequal diameters, such'discssubsequently being secured together by a suitable adhesive.

It is a general aim of the present invention to provide an improvedcontainer construction, and method of manu- .f-acture'thereof, whichovercomes all of the foregoing disadvantages and which is characterizedby its ease of manufacture.

More specifically, it is an object of the invention to provide alaminated or multiple layer fibrous end member for shipping containerswhich permits of an improved seamed connection between the body and endmembers, which connection is characterized by its strength, tightness,and resistance to deformation forces of the type normally encountered inhandling, transportation and'storage. While not so limited in itsapplication, the invention will find especially advantageous use inconnection with vshipping containers of the type which not only employlaminated tibrous'end members, but which also employ laminar fibrousbody walls made, for example, by convolutely or helically winding a webof fibrous sheet malterial about a forming mandrel or the like.

A further object of the invention is the provision of an improved seamedconnection between the body yand laminated, fibrous end walls of ashipping container which permits of the use of relatively inexpensiveand weak fibrous material in the central layer of a multiple layer orsandwhich type container closure, yet which is neverthelesscharacterized by its strength and reliability in use. As a consequenceof attaining this objective, containers embodying the present inventionmay be made at lower cost by economizing in material quality, materialcosts,

and labor, while at the same time the resultant container will bestronger than those heretofore known in the prior art.

In another of its important aspects, it is an object of the invention toprovide an improved container end connection employing at least threelaminations of fibrous sheet material, and to improved methods ofmanufacture thereof, wherein the relatively weak central fibrouslamination is maintained substantially free of tensile forces duringboth the seaming operation and in the field when, for example, a heavilyloaded container is subjected tovshocks or vibrations, and whereinsubstantially all of the stress is absorbed by the relatively strongouter layers or laminations.

An ancillary object of the invention is the provision of a novelreinforced end connection between the body and end Wallsof a fibrousshipping container and which permits use of a lighter gauge metallicreinforcing ring than 1s commonly employed with conventional reinforcedcontainer constructions, yet wherein substantially the same degree ofstrength and protection is afforded the seamed connection by thelightweight metallic reinforcing ring as has heretofore been affordedthe seamed connection of conventional containers employing heavier gaugemetallic reinforcing rings.

Other objects and advantages of the invention will become apparentes thefollowing description proceeds, taken in conjunction with theaccompanying drawing, in which:

FIGURE 1 is a side elevation of a shipping container embodying thefeatures of the present invention;

FIG. 2 is a vertical cross-sectional view on an enlarged scale takensubstantially along the line 2 2 in FIG. l, here depicting details ofthe improved connection between the body and end walls of the exemplarycontainer;

FIG. 3 is a vertical cross-sectional view similar to FIG. 2, hereillustrating the novel container end connection duringdan initial stagein the method of manufacture thereof; an

FIG. 4 is an enlarged vertical cross-sectional view similar to a portionof FIG. 2, but here depicting a slightly modified end wall constructionlalso embodying the features of the present invention.

While the invention is susceptible of various modifications andalternative forms, a specic embodiment thereof has been shown by way ofexample in the drawing and will herein be described in detail. It shouldbe understood, however, that it is not intended to limit the inventionto the particular form disclosed, but, on the contrary, the intention isto cover all modifications, equivalents and alternatives falling withinthe spirit and scope of the invention as expressed in the appendedclaims.

Referring more particularly to the drawing, there is illustrated in FIG.1 an exemplary shipping container, generally indicated at 10, made inaccordance with `the present invention. As best illustrated in FIG. 2,the exemplary container includes a body wall 11 and a closure or endmember, generally indicated Iat 12, the wall I111 and end member 12being seamed together as shown at 14. In this instance the en-d member12 constitutes the container bottom. However, as the ensuing descriptionproceeds, it will bec-ome apparent that a similar end member could alsobe secured to the upper end of the body wall 11 in accordance with theinvention, thus providing a container top (not shown). In this latterevent, it would simply be necessary to provide suitable means forIfilling the container and for subsequently discharging the contentsthereof such,l for example, as the provision of a filling anddischarging orifice or, alternatively, by making t-he body wall 1|1 oftwo separable portions.

In the illustrative container 10, the end member 12 is of asandwich-type construction, consisting 4of an inner central layer orlamination 15 sandwiched between a pair of outer layers or laminations16. The individual laminations may be made of a wide variety ofcommercially available fibrous sheet materials such, for example, asfiber, paper, or -other natural or synthetic materials. However, inorder to facilitate the ensuing description, the in vention will bedescribed in conjunction with a cylindrical container 10 having an endmember 12 consisting of an inner or central layer 15 of relatively weakand inexpensive paperboard such, for example, as millboard or chipboard,the central layer being sandwiched between a pair of relatively strongfibrous outer layers 16 which, merely by way of example, may comprisesheets of kraft liner board. Similarly, the body wall -11 of thecontainer may also be formed of suitable fibrous materials. For example,the body wall may be of laminar construction (not shown) and formed of aweb of kraft paper or the like wound convolutely or helically about asuitable forming mandrel. Moreover, the body wall may, if desired, haveother than the cylindrical configuration shown.

In accordance with one `of the `important aspects of the presentinvention, provision is made :for seaming the end member 12 to the bodywall 11 in such a manner as to form a seamed end connection 14characterized by its strength and tightness and wherein the tendency ofthe end member 12 to pull out of the seamed connection is `substantiallyeliminated. To 'accomplish this, the end member 12 is formed of aplurality of equidimensional laminations 15, 16 as measured in atransverse direction; eng., where the container is cylindrical as hereshown, the layers 15, 16 have equal or substantially equal dia-metersand, the initial diameter of all layers exceeds the internal diameter ofthe container Wall. As a consequence of this construction, when theperipheral edge of the end member 12 is folded over with the marginalextremity of the body wall by means well known to those skilled in theart, all of the layers or laminations which make up the end member arefolded' into the seamed connection 14.

In the illustrative form of `the invention, the body wall 11 of thecontainer 10 has formed therein an inwardly extending circumferentialrib 18 which is formed adjacent the marginal extremity of the body wall.Thus, when the endmember 12 and body wall 11 are seamed together, anannular portion of the end member is securely clasped or clamped betweenthe seamed connection 14 and the rib 18, thus enhancing the strength ofthe connection.

-In order to further enhance the strength of the connection 14 and toincrease its resistance to deformation forces, a metallic reinforcingring -19 may be positioned in proximity to the connection Iprior to theseaming operation, for example, by placing the ring 19 in surroundingrelation to the margin-al extremity of the body wall 11. Thus, when thebody wall 11 and end member 12 are seamed together, the reinforcing ring19 is folded over with the body Wall and end member with the freeextremity of -the ring 19 being clamped in the seamed connection. Ofcou-rse, the ring 19 could be secured to the container in other ways andstill serve to reinforce the resultant im proved connection. Forexample, the ring L19 could be mounted within the fold seam 14 and itsedge similarly folded over together with the peripheral edge of the endmember 12 and the marginal extremity of the body wall 11.

In keeping with the preferred form of the invention, the end member 12comprises at least three layers of fibrous material. The cent-ral layer15, which provides the body of the end member, is formed of paperboardor the like, and it serves to space the relatively stronger outer layers16 apart, thus providing additional strength. Since `the central layer15 is sandwiched between relatively stronger outer layers 16, the latterpreferably being made of kraft liner board or the like, the centrallayer can be made of fibrous material of relatively poorer quality suchas millboard or chipboard. Although the poorer quality millboard orchipboard is normally not capable of withstanding the deformationresulting from the seaming operation, the protection afforded by thestronger outer layers 16 prevents cracking or breaking of the centrallayer as the latter is folded. In actuality, deformation of thelaminated end member 12 during the seaming operation causes, at most,delamination of the central layer into several layers which `slide overone another but which each remain intact and do not break. As aconsequence, a great number of unbroken layers separated from oneanother by delamination are embedded in the seamed connection 14, thussubstantially enhancing the strength of the latter. 'It has been foundthat when containers made in accordance with the invention are subjectedto deformation forces, for example, forces resulting from prescribeddroptest techniques well known to those skilled in the art, the endmembers 12 do lnot pull out of the seamed connection 14 and the latterremains tight.

In carrying out the invention, provision may also be made for improvingthe wear resistance of the end member 12. To this end, the outermost orexternal layer 16 (e.g., the lowermost layer 16 as viewed in FIG. 4) maybe coated or impregnated with a bituminous liner 17- While such a lineris water repellant, it does not afford a moisture barrier and,consequently, in keeping with this aspect of the invention, the'bituminous liner may be laminated to the layer 16 by means of a layer17 of bitumen.

To facilitate assembly of the body Wall 11 and end member 12, the latteris initially formed with an upstanding peripheral flange 20 (FIG. 3),for example, by bending the edge of the laminar end member out of theplane of the central disc portion thereof. Thus, it is merely necessaryto insert the end member 12 into the opening defined by the body wall 11until it seats against the rib 18 with the ange 20 engaging the innersurface of the body wall. The flange 20 and body wall 11 are then seamedtogether. i

In accordance with another of the important aspects of the presentinvention, provision is made for controlling lthe internal stressesdeveloped in the end member =12 during a seaming or folding operation.To this end, a-t least the outermost layers 16 of the end member 12 areput under radial tension during the seaming operation. To ac complishthis, the peripheral ange 20 is preferably formed with a slight taper(as best shown in FIG. 3) so that the ange 20 flares outwardly from theend member 12. The degree of taper is such that the maximum diameter ofthe tapered flange is substantially equal to -the internal d1- ameter ofthe body wall 11 while the smallest diameter of the tapered ange isconsiderably less than the internal diameter of the body wall 11. Thus,during a seaming operation the end member 12 is effectively placedunderV a radial tension. As the seaming operationprogresses, the freeextremity of the body wall 11 is compressed or contracted, therebytending to expand the latter so as to increase, or at the very least, tomaintain the tension in the outer layers 16 of the end member y12 uponremoval of the container from the seaming apparatus.

It will be appreciated from the foregoing description, that the presentinvention also contemplates novel methods for forming containers of thetype having laminar fibrous end walls joined to the container body wall.Thus, 1n manufacturing containers 10 in accordance with the invention, aperipherally continuous body wall 11 is formed, the wall preferablyhaving a circumferential, inwardly extending rib 18 formed therein. Inthose instances where the body wall 11 is also of laminar brousconstruction, the w-all may be formed in a conventional manner as, forexample, by convolutely or helically winding a web of sheet materialabout a forming mandrel. A laminated end member is then formed bysandwiching a sheet of paperboard or the like between axially spacedlayers of relatively stronger fibrous material such as kraft linerboard. The individual laminations or layers have like transversedimensions and all are initially formed lslightly largerthan theinternal dimension of the body wall 11. The peripheral edge of the endmember 12 is bent to form an upst-anding flange either prior to orincident to insertion of the end member into the opening in the bodywall 11, rand the flange thus formed'is then folded over with themarginal extremity of the body wall 11 to form a novel seamed connection14. The rib 18 formed in the body wall 11 serves 'as a seat for the endmember 12, thus insuring that when the two pieces are seamed together,an annular portion of the latter is clamped bet-Ween the rib and theseamed connection. Still greater strength is achieved by positioning ametallic reinforcing ring in proximity to the seamed connection prior toa seaming operation and simultaneously folding the ring, body wallextremity, and peripheral edge of the end member together to form areinforced seam.

In forming containers in accordance with the preferred method of theinvention, the end member 12 is placed under radial tension during theseaming operation, that is, the outer layers 16 are subjected to radialtensile forces during the seaming operation and, since seaming causesthe body wall to tend to expand in the vicinity of the plane of the endmember, such radial tension is maintained even after the container isremoved from the seaming apparatus. It has been found that this servesto increase the resistance of the end member 12 to bending loads,

shock, blows, and vibrations. Thus, the outer layers 16 of vthe endmember -act as a membrane or diaphragm clamped tight about itsAperiphery, and substantially all of the stresses incurred are taken upby the relatively strong outer layers 16.

It will be observed that since the present invention contemplateslaminar end members 12 having equal diameters, the different layers maybe glued or otherwise bonded together in laminar form while in the sheetor web state, thus permitting completely formed end members to beblanked directly from the sheet or web thus formed. This, of course,insures substantial savings in both time and expense over the prior artconstructions wherein the various layers had different diameters, thusrequiring that each lamination be prebl-anked prior to its assembly withadjacent laminations.

Of course, those Skilled in the art will appreciate that the outerlayers 16 of the container bottom may possess other characteristics inaddition to being stronger than the central layer 15. For example, oneor both of the layers 16 may be formed of a liquid impervious material.Alternatively, the outermost layer 16 (i.e., the bottom layer as viewedin FIG. 2) may have liquid repellant properties while the internal layer16 (i.e., the top layer as viewed in FIG. 2) may be liquid impervious.

It has been found that containers embodying the features of the presentinvention are characterized by their strength and durability,particularly in the region of the seamed connection 14. Moreover, inthose instances where the container requires additional protection inthe form of a reinforcing ring 19, the latter can be formed of `alighter gauge metal than is conventionally used while still attainingthe same degree of additional reinforcement.

We claim as our invention:

y1. A shipping container comprising, in combination, a body wall, an endWall, said end Wall being formed of at least three laminations of sheetmaterial with said laminations being substantially equidimensionaltransversely thereof and having an initial diameter greater than theinternal diameter of the body Wall, the outermost ones of saidlaminations being formed of relatively strong fibrous materialsandwiching the central lamination, said central lamination being formedof fibrous material relatively weaker than the fibrous material definingsaid outermost laminations, the peripheral edges of all of saidlaminations being bent out of the plane of said end wall to define alaminated peripheral flange surrounding a central disc portion of saidend wall, and said ange and the marginal extremity of said body wallbeing folded together inwardly beneath said c'entral disc portion todefine a fold seam connection therebetween rigidly securing said endwall to said body wall.

2. A shipping container as set forth in claim 1 further characterized inthat said outermost laminations are formed of kraft liner board and saidcentral lamination is formed of paperboard.

3. A shipping container as set forth in claim 2 further characterized inthat said central lamination is formed of millboard.

4. A shipping container as set forth in claim 2 further characterized inthat said central lamination is formed of chipboard.

5. A shipping container as set forth in claim 1 further characterized inthat the external one of said outermost laminations is coated with alayer of bituminous liner material.

6. A shipping container as set forth in claim 5 further characterized inthat said layer of bituminous liner maa layer of bitumen.

7 8 teri'al is laminated to the adjacent lamination by means of2,968,415 1/1961 Brown 21S-40 2,989,218 6/ 1961 Bergstrom 229--5.5References Cited by the Examiner 2 5 63 8/ FOREIFGN PATENTS 0 0 1959rance. 5 1 Y UNITED STATES PATENTS 77,387 9/19750' Norway.

5/1912 Angler. 10/ 1914 Sinclair 229--5 .6 JOSEPH R. LECLAIR, PrimaryExaminer. l 21f1;;1111111 22219533 FRANKLIN T- GARRETR Examine 4/1959Carpenter et a1. 229-56 10 v. A. TOMPSON, J. F. MCNULTY, AssistantExaminers.

1. A SHIPPING CONTAINER COMPRISING, IN COMBINATION, A BODY WALL, AN ENDWALL, SAID END WALL BEING FORMED OF AT LEAST THREE LAMINATIONS OF SHEETMATERIAL WITH SAID LAMINATIONS BEING SUBSTANTIALLY EQUIDIMENSIONALTRANSVERSELY THEREOF AND HAVING AN INITIAL DIAMETER GREATER THAN THEINTERNAL DIAMETER OF THE BODY WALL, THE OUTERMOST ONES OF SAIDLAMINATIONS BEING FORMED OF RELATIVELY STRONG FIBROUS MATERIALSANDWICHING THE CENTRAL LAMINATION, SAID CENTRAL LAMINATION BEING FORMEDOF FIBROUS MATERIAL RELATIVELY WEAKER THAN THE FIBROUS MATERIAL DEFININGSAID OUTERMOST LAMINATIONS, THE PERIPHERAL EDGES OF ALL OF SAIDLAMINATIONS BEING BENT OUT OF THE PLANE OF SAID END WALL TO DEFINE ALAMINATED PERIPHERAL FLANGE SURROUNDING A CENTRAL DISC PORTION OF SAIDEND WALL, SAID FLANGE AND THE MARGINAL EXTREMITY OF SAID BODY WALL BEINGFOLDED TOGETHER INWARDLY BENEATH SAID CENTRAL DISC PORTION TO DEFINE AFOLD SEAM CONNECTION THEREBETWEEN RIGIDLY SECURING SAID END WALL TO SAIDBODY WALL.